Burglar alarm



April 12, 1932.

BURGLAR ALARM Filed July 25, 1951 FIE'EI.

J3 INVENTOR. u. E, FEE 5 US UN.

Mfm/Q ATTORNEYS.

D. E. FERGUSON 1,854,126

Patented Apr. 12, 1932 UNITED STATES DAVID E. FERGUSON, OF LONG BEACH, CALIFORNIA BURGLAR ALARM Application filed July 25,

This invention relates to improvements in burglar alarms.

The principal object of this invention is to provide an alarm which may be attached to 5 a window or door for the purpose of giving a warning when the door or window is: opened by an unauthorized person.

A still further object is to produce a device of this character wherein the door or window 19 may be opened when desired without actuating the alarm.

A still further object is to produce a device of this character which will give a shrill warning-differentiating from an ordinary bell.

A still further object is to produce a device of this character which is economical to manufacture and simple in construction.

Other objects and advantages will be apparent during the course of the following description.

In the accompanying drawings forming a part of this specification and in which like nun merals are employed to designate like parts throughout the same,

Figure 1 is a side elevation of my device as the same would appear when secured to a window frame,

Figure 2 is a front elevation of Fig. -1,

Figure 3 is a side elevation of my device as the same would appear when attached to a door frame, 7

Figure 4 is a front elevation of Fig. 3,

Figure 5 is an enlarged side elevation of my mechanism with the cover removed,

Figure 6 is a front elevation of my mechanism with the cover removed,

Figure 7 is a bottom plan view showing the trigger mechanism, and

Figure 8 is a fragmentary detail view of the spring pawl.

Applicant is aware of the fact that burglar alarms have been in use wherein a bell is n employed. These bells are ordinarily of low pitch and therefore, do not give a suflicient warning to wake a person who is soundly sleeping, or to notify a person at a considerable distance. m With my device I employ a diaphragm which is rapidly vibrating so that a very 1931. serial No. 553,182.

shrill sound is given which would be sufficient to warn a person, and at the same time to drive away the unauthorized person.

In the accompanying drawings wherein for the purpose of illustration 1s shown a preferred embodiment of my invention, the numeral .5 designates a window casing and the numeral 6 a window frame. Upon the window frame I pivotally support a bracket 7 which is adapted to engage a bell crank i.

lever 8, pivotally supported as at 9below the alarm box designated as a whole by the numeral 11. The structure shown in Figs' 3 and 4 is identical with the exception that upon the door 12 is positioned a. pivoted lever 13 which is adapted to strike the latch 14 which extends from the box 11. Referring to Figs. 5, 6 and 7, the cover of the box has been removed so that the mechanism therein may be viewed. At 16 I have shown a spring mounted upon a shaft 17 to which is attached a ratchet 18 which is engaged by a dog 19. This permits a key to be placed upon the end 21 of the. shaft 17 for the purpose of winding the spring. Secured to the shaft is gear 22 which meshes with a gear 23 mounted upon the shaft 24. A gear 25 in turn meshes with a gear 26 mounted upon the shaft 27. A star wheel 29 ismounted' upon the shaft27 and'has its teeth in aligntrated in Fig.7) may be moved between the teeth of the star wheel. The spring 36 has one end attached to the housing and has its opposite end attached to an arm 37 of the latch (see Fig. 5). This spring is attached to the latch invsuch a manner that it-will normally over-lie dead center when the latch 14 is in position ready to be struck. TlllS spring assists the latch to fly out of engagement with the teeth of the star wheel when the slightest movement of the latch occurs.

It will thus be seen that when the parts are arranged as shown in the figures and the spring 16 has been placed under tension, that the raising of the window will cause the bracket 7 to engage the bell crank lever 8 which will move the latch 14 and the spring 36 will then function to throw the eccentrically mounted latch a sufficient distance so that its bevelled end 34 will be moved out 5 of engagement with the teeth of the star wheel 29. Immediately the spring will function thru the gearing and cause the teeth of the-star wheel to rapidly pass over the end 31 of the spring 32 thus vibrating the diaphragm 33 and giving a shrill Warning sound. In the case of the door, the action will be the same with the exception that the lever 13 will perform the function of operating the latch. It is of course understood that 15 the lever 13 may be either placed upon the right-hand side of the door or the left hand side, as the occasion demands.

It is to. be understood that the form of my invention herewith shown and described is to. be taken as a preferred example of the same and that various changes relative to thermaterial, size, shape 'andarrangement of parts may be resorted to without departing from the spirit of the invention or the scope ofthe subjoined claims.

Having thus described my invention, I claim 1..In:a device of the character described, ahonsing, a. driven gear positioned within said.housing, a star wheel adapted to be rotated by said gearing, a pivoted latch eccentrically mounted-in said housing and having one end. thereof extending from said housing, the opposite end of said latch engaging the. teeth of said star wheel, a diaphragm positioned in said housing, a spring connectedto: said diaphragrnand havingits free endsnccessively engagedby'the teeth of said star wheel. v 40 2.. Inv a device of the character described, a housing, a driven gear. positioned within said housing, a star; wheel adapted to be rotated .by said gearing, a pivoted latch eccentrically mountedin saidhousing and having one'end thereof extendingfrom saidlhousing, the opposite end of said latch engaging the teeth of said star wheel, a. diaphragm posi tionedin said housing, aspring connectedlto said diaphragm and having its free-endv suc- 59 cessivelyengaged. bythe teeth of'said. star wheel, and a spring connected to said latch whereby when said latch; is contacted said spring Willf'unctiontomove said latch and withdraw its end from engagement with the 5 teeth ofsaid star wheel.

In testimony whereof I aflix my signature.

DAVID. E. FERGUSON. 

